Mylar beam-splitter efficiency in far infrared interferometers: angle of incidence and absorption effects
Abstract
Absorption and complete multipath interference have been included in the calculation of the modulation efficiency of a far IR Michelson interferometer with 25-micron and 100-micron Mylar beam splitters over the range of wavenumbers between 20 cm to the -1 and 125 cm to the -1 for angles of incidence between 45 deg and 80 deg. These results show that optimum performance of an interferometer in terms of highest and most uniform modulation efficiency for unpolarized radiation will be obtained by selecting the beam-splitter thickness to cover the wave-number range of interest within the first interference lobe and by utilizing higher angles of incidence than the mechanically convenient 45 deg. Practical constraints will usually limit this angle to a value somewhat less than the optimum of about 75 deg for Mylar beam splitters.
- Publication:
-
Applied Optics
- Pub Date:
- April 1978
- DOI:
- 10.1364/AO.17.001055
- Bibcode:
- 1978ApOpt..17.1055N
- Keywords:
-
- Beam Splitters;
- Far Infrared Radiation;
- Infrared Absorption;
- Infrared Interferometers;
- Michelson Interferometers;
- Mylar (Trademark);
- Dielectrics;
- Diffraction Patterns;
- Incident Radiation;
- Light Modulation;
- Thin Films;
- Transmission Efficiency;
- Instrumentation and Photography;
- BEAM SPLITTERS;
- INFRARED: FAR;
- INTERFEROMETERS